The classic Sherlock Holmes story. Well implemented, well played.

The acting and chemistry of Peter Cushing and Christopher Lee make this Hammer flick worth watching. Its greatest flaw may be the lack of geography. You get no idea were places are in relation to each other, there are very few exterior shots. Seems like it was all done in a studio with leftover sets. I think geography is very important in detective stories for both internal logic and atmosphere.

Not only it has nothing to do with the novel, but the movie is extremely stupid and boring.

Peter Cushing should have reprised the role, he was perfect as Sherlock Holmes. This kind of breezes through plot points, characters come and go, and it's all a bit cheesy. But it's a very comfy watch due to the great acting, brisk pace, and comfy ending.